Avisynth basic editing question

So I've been trying to get some basic video editing done with Avisynth, but I can't figure out how to do what I want, and there doesn't seem to be any tutorial covering it.

So basically I have 2 clips that I load in Avisynth. This part I can get right.
The problem starts when I want to edit some parts off the first clip.
None of the commands that work for trimming and fading a clip when working with a single clip work anymore.